Most colorectal cancers arise from adenomatous polyps of the large bowel. Patients who have had one or more adenomas removed are at an increased risk of developing multiple sequential (metachronous) or recurrent adenomas. Studies assessing predictors for recurrent adenomas will provide valuable information for designing individualized, cost-effective, surveillance strategies for adenoma patients after initial polypectomy. This proposed study will build upon a recently completed case-control study in Minnesota, in which 574 incident adenoma patients were recruited and comprehensive information on environmental and lifestyle factors and pathologic characteristic of the initial adenomas were collected. Blood samples from these patients were also obtained and are currently being analyzed for polymorphisms of the familial polyposis gene (APC) and genes that encode N-acetyltransferases (NAT) and glutatathione S-transferase (GST). The investigators propose to follow these adenoma patients for 5 years to assess potential predictors for recurrent adenomas. In addition to the above mentioned existing data, paraffin embedded tissue blocks of the initial adenomas will be collected from all patients and analyzed for selected tumorigenesis markers, k-ras and p53 gene mutations and cell proliferation activity. These tumorigenesis markers will be analyzed along with previously collected data on lifestyle factors, pathologic characteristics of incident adenomas, and genetic susceptibility markers, in relation to adenoma recurrence. The feasibility of the study has been clearly demonstrated in our pilot studies. Further, because the study population is well characterized and a large proportion of data has already been collected, the proposed study will be extremely cost-effective. The results of this study are likely to have great implications for cost-effective managed care of adenoma patients to reduce morbidity and mortality of colorectal cancer, one of the most common malignancies in this country.